ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), (e.g. graphite).
Brittle, Metallic, Brittle, Metallic, Brittle, Metallic
{110} Distinct, {001} Indistinct, {100} Indistinct
Perfect on {010}, indistinct on {100} and {102}